1. Field of the Invention
The present invention generally relates to a clamping device for use in jewelry manufacture or repair and, in particular holding ring shank and crown in position during soldering.
2. Brief Description of the Prior Art
Jewelers commonly manufacture unique rings by connecting a ring head or crown to a ring shank. The problem of aligning the head or crown has always existed in the jewelry industry. Jewelers have tried to hold the ring parts in place in an aligned position with locking tweezers. However there are many problems with tweezers. For one, the tweezers arms are not parallel thus making it difficult to line up the parts of the ring from every angle. Also, standard tweezers do not have a gripping element in which a crown and shaft can be securely held in place. The lack of gripping element coupled with unequal pressure exerted by the tweezers arms allows the ring parts to shift during soldering. This procedure is done by a craftsman in the art mostly “by eye” and it is not uncommon the soldering has to be repeated many times before the ring is constructed in a true alignment.
Furthermore, with the prior art methods and apparatus, the prongs of the crown get overheated because of the high temperature of the flame during the soldering procedure and the lack of a heat sink. The extreme heat creates firescale that has to be removed by polishing the prongs. When a prong is over-polished a less ascetically pleasing work is produced. This over-polishing also removes metal and creates weak prongs. Since the prong secures the gemstone to the ring, a weaker prong increases the chance the gemstone may be lost. Prior attempts have been made to mitigate the problems associated with soldering component parts of rings together. For example:
In the February 2002 edition of Professional Jewelers magazine, Vol. 5, No. 2, on page #96 an article entitled, “Modified Tweezers” describes an improved tweezers design. The article offers a very crude way to solve the problem of non-parallel tweezers arms. In the procedure described, a pair of standard tweezers is modified by splitting and spreading one end to provide broad support to hold shanks. The other side is shortened and a shortened setting bur is silver-soldered on it. The bur fits into the head or crown and thus provides a heat sink for the prongs. But the size of the bur limits the size of the crown or head that can be used. Also this device does not hold the prongs true to the shank, it requires excess pressure to hold the parts in place, it provides very inefficient heat sink and the device has to be adjusted by bending the apparatus.
Various C-shaped clamps, presses or the like are known for other purposes in the manufacture of jewelry rings. For example, U.S. Pat. No. 2,962,796 to Bick relates to a jewelers' device for enlarging a ring. This invention employs an arm that moves upwardly and downwardly. However this arm presses the ring into the base or anvil that is configured to hold the ring while the ram is forced into the ring thus enlarging the ring.
U.S. Pat. No. 4,329,890 to Ferstenberg discloses a device for setting precious stones in bezels with claws, mounted on rings or similar, characterized by the combination of: a receptacle; a support for a ring or similar at least partially engageable into said receptacle; a device for maintaining a stone placed into the bezel of ring or similar, said support being engaged into the receptacle and a setting device, all aforesaid devices and support being functionally integral with one another at least when the device is in setting position.
U.S. Pat. No. 4,077,284 to Twichell Shostak discloses a stone setting press for securely fastening stones to settings comprising an arbor supported on a frame or base, shaped to receive and support a ring setting. A forming die at the end of a shaft is shaped to deform the prongs of a setting about a stone. The shaft is supported on the frame for axial movement to and from a position in which the die shapes the prongs. A leverage system having variable mechanical advantage is used to actuate the shaft.
The present invention seeks to alleviate the problems associated with the prior art devices.